Europe-wide 380 matches and 425 people within the game have been investigated, however Del Bosque made clear that he "never saw it" happen.
"I don't have anything new to say about the matter," AS quotes Del Bosque as saying.
"I never saw it, not as a player or as a coach, nor do I think I'll see it in the future.
"I'd rather be naive than think it goes on. I've never seen anything ever. It's a subject I'd rather avoid."
Spain play Uruguay in a friendly on Wednesday night.